From ec3d41c4db4c21164332826ea8d812f94f2f6886 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 22 Oct 2007 11:03:36 +1000 Subject: Virtio interface This attempts to implement a "virtual I/O" layer which should allow common drivers to be efficiently used across most virtual I/O mechanisms. It will no-doubt need further enhancement. The virtio drivers add buffers to virtio queues; as the buffers are consumed the driver "interrupt" callbacks are invoked. There is also a generic implementation of config space which drivers can query to get setup information from the host. Signed-off-by: Rusty Russell Cc: Dor Laor Cc: Arnd Bergmann --- drivers/virtio/Kconfig | 3 + drivers/virtio/Makefile | 1 + drivers/virtio/config.c | 13 ++++ drivers/virtio/virtio.c | 171 ++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 188 insertions(+) create mode 100644 drivers/virtio/Kconfig create mode 100644 drivers/virtio/Makefile create mode 100644 drivers/virtio/config.c create mode 100644 drivers/virtio/virtio.c (limited to 'drivers/virtio') diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig new file mode 100644 index 000000000000..bce84b56a659 --- /dev/null +++ b/drivers/virtio/Kconfig @@ -0,0 +1,3 @@ +# Virtio always gets selected by whoever wants it. +config VIRTIO + bool diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile new file mode 100644 index 000000000000..af0d57dad3eb --- /dev/null +++ b/drivers/virtio/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_VIRTIO) += virtio.o diff --git a/drivers/virtio/config.c b/drivers/virtio/config.c new file mode 100644 index 000000000000..983d482fba40 --- /dev/null +++ b/drivers/virtio/config.c @@ -0,0 +1,13 @@ +/* Configuration space parsing helpers for virtio. + * + * The configuration is [type][len][... len bytes ...] fields. + * + * Copyright 2007 Rusty Russell, IBM Corporation. + * GPL v2 or later. + */ +#include +#include +#include +#include +#include + diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c new file mode 100644 index 000000000000..f640e0b732b7 --- /dev/null +++ b/drivers/virtio/virtio.c @@ -0,0 +1,171 @@ +#include +#include +#include + +static ssize_t device_show(struct device *_d, + struct device_attribute *attr, char *buf) +{ + struct virtio_device *dev = container_of(_d,struct virtio_device,dev); + return sprintf(buf, "%hu", dev->id.device); +} +static ssize_t vendor_show(struct device *_d, + struct device_attribute *attr, char *buf) +{ + struct virtio_device *dev = container_of(_d,struct virtio_device,dev); + return sprintf(buf, "%hu", dev->id.vendor); +} +static ssize_t status_show(struct device *_d, + struct device_attribute *attr, char *buf) +{ + struct virtio_device *dev = container_of(_d,struct virtio_device,dev); + return sprintf(buf, "0x%08x", dev->config->get_status(dev)); +} +static struct device_attribute virtio_dev_attrs[] = { + __ATTR_RO(device), + __ATTR_RO(vendor), + __ATTR_RO(status), + __ATTR_NULL +}; + +static inline int virtio_id_match(const struct virtio_device *dev, + const struct virtio_device_id *id) +{ + if (id->device != dev->id.device) + return 0; + + return id->vendor == VIRTIO_DEV_ANY_ID || id->vendor != dev->id.vendor; +} + +/* This looks through all the IDs a driver claims to support. If any of them + * match, we return 1 and the kernel will call virtio_dev_probe(). */ +static int virtio_dev_match(struct device *_dv, struct device_driver *_dr) +{ + unsigned int i; + struct virtio_device *dev = container_of(_dv,struct virtio_device,dev); + const struct virtio_device_id *ids; + + ids = container_of(_dr, struct virtio_driver, driver)->id_table; + for (i = 0; ids[i].device; i++) + if (virtio_id_match(dev, &ids[i])) + return 1; + return 0; +} + +static struct bus_type virtio_bus = { + .name = "virtio", + .match = virtio_dev_match, + .dev_attrs = virtio_dev_attrs, +}; + +static void add_status(struct virtio_device *dev, unsigned status) +{ + dev->config->set_status(dev, dev->config->get_status(dev) | status); +} + +static int virtio_dev_probe(struct device *_d) +{ + int err; + struct virtio_device *dev = container_of(_d,struct virtio_device,dev); + struct virtio_driver *drv = container_of(dev->dev.driver, + struct virtio_driver, driver); + + add_status(dev, VIRTIO_CONFIG_S_DRIVER); + err = drv->probe(dev); + if (err) + add_status(dev, VIRTIO_CONFIG_S_FAILED); + else + add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); + return err; +} + +int register_virtio_driver(struct virtio_driver *driver) +{ + driver->driver.bus = &virtio_bus; + driver->driver.probe = virtio_dev_probe; + return driver_register(&driver->driver); +} +EXPORT_SYMBOL_GPL(register_virtio_driver); + +void unregister_virtio_driver(struct virtio_driver *driver) +{ + driver_unregister(&driver->driver); +} +EXPORT_SYMBOL_GPL(unregister_virtio_driver); + +int register_virtio_device(struct virtio_device *dev) +{ + int err; + + dev->dev.bus = &virtio_bus; + sprintf(dev->dev.bus_id, "%u", dev->index); + + /* Acknowledge that we've seen the device. */ + add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE); + + /* device_register() causes the bus infrastructure to look for a + * matching driver. */ + err = device_register(&dev->dev); + if (err) + add_status(dev, VIRTIO_CONFIG_S_FAILED); + return err; +} +EXPORT_SYMBOL_GPL(register_virtio_device); + +void unregister_virtio_device(struct virtio_device *dev) +{ + device_unregister(&dev->dev); +} +EXPORT_SYMBOL_GPL(unregister_virtio_device); + +int __virtio_config_val(struct virtio_device *vdev, + u8 type, void *val, size_t size) +{ + void *token; + unsigned int len; + + token = vdev->config->find(vdev, type, &len); + if (!token) + return -ENOENT; + + if (len != size) + return -EIO; + + vdev->config->get(vdev, token, val, size); + return 0; +} +EXPORT_SYMBOL_GPL(__virtio_config_val); + +int virtio_use_bit(struct virtio_device *vdev, + void *token, unsigned int len, unsigned int bitnum) +{ + unsigned long bits[16]; + + /* This makes it convenient to pass-through find() results. */ + if (!token) + return 0; + + /* bit not in range of this bitfield? */ + if (bitnum * 8 >= len / 2) + return 0; + + /* Giant feature bitfields are silly. */ + BUG_ON(len > sizeof(bits)); + vdev->config->get(vdev, token, bits, len); + + if (!test_bit(bitnum, bits)) + return 0; + + /* Set acknowledge bit, and write it back. */ + set_bit(bitnum + len * 8 / 2, bits); + vdev->config->set(vdev, token, bits, len); + return 1; +} +EXPORT_SYMBOL_GPL(virtio_use_bit); + +static int virtio_init(void) +{ + if (bus_register(&virtio_bus) != 0) + panic("virtio bus registration failed"); + return 0; +} +core_initcall(virtio_init); -- cgit v1.2.2